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Biomedical subjects

J Janssens

Publications and source records attributed to J Janssens.

At least 19 recordsLinked to original sources
PubMed1998

Role of impaired gastric accommodation to a meal in functional dyspepsia.

BACKGROUND & AIMS: Impaired accommodation of the proximal stomach to a meal has been reported in functional dyspepsia, but its relevance to symptoms is unclear. The aim of this study was to test the hypothesis that impaired gastric accommodation causes early satiety. METHODS: A gastric barostat was used to study postprandial fundus relaxation in 35 healthy subjects and 40 patients with functional dyspepsia. Gastric emptying, Helicobacter pylori status, sensitivity to gastric distention, and a dyspepsia symptom score were obtained from all patients. In addition, the effect of sumatriptan, a fundus-relaxing 5-hydroxytryptamine1 agonist, on gastric accommodation and on early satiety in dyspeptic patients was studied. RESULTS: Impaired gastric accommodation to a meal was found in 40% of the patients. In univariate analysis, this was associated with early satiety and weight loss but not with hypersensitivity to gastric distention, presence of H. pylori, or delayed gastric emptying. In a multivariate analysis, only early satiety was associated with impaired gastric accommodation. Sumatriptan restored gastric accommodation, thereby significantly improving meal-induced satiety. CONCLUSIONS: Impaired relaxation of the proximal stomach to a meal is present in a high proportion of patients with functional dyspepsia. It is associated with symptoms of early satiety. Restoring gastric accommodation with a fundus-relaxing drug improves early satiety.

Adult↗
PubMed1998

The influence of cisapride on gastric tone and the perception of gastric distension.

BACKGROUND: Delayed gastric emptying, impaired gastric accommodation to a meal and hypersensitivity to gastric distension have been implied in the pathophysiology of functional dyspepsia. Dyspeptic patients are often treated with the prokinetic drug cisapride. AIM: To assess the effects of cisapride on perception of gastric distension and gastric accommodation to a meal. METHODS: Eighteen healthy volunteers underwent a gastric barostat study on two occasions, after pretreatment with placebo or cisapride 10 mg q.d.s. Graded isobaric and isovolumetric distensions were performed until the subjects reported discomfort. Volume and pressure changes were recorded and perception was scored by a questionnaire. In 10 volunteers, the amplitude of the gastric accommodation to a mixed liquid meal was also measured. RESULTS: Pre-treatment with cisapride significantly lowered thresholds for perception and for discomfort, both during isobaric (4.3 +/- 0.7 vs. 3.2 +/- 0.7 and 12.2 +/- 1.2 vs. 9.2 +/- 0.9 mmHg above minimal distending pressure (MDP), respectively, P < 0.05) and isovolumetric (256 +/- 46 vs. 200 +/- 35 and 644 +/- 36 vs. 511 +/- 40 mL, respectively, P < 0.05) distensions. Cisapride significantly enhanced the size of the meal-induced fundus relaxation (143 +/- 37 vs. 270 +/- 50 mL, P < 0.05). CONCLUSIONS: Cisapride enhances both the perception of gastric distension and the gastric accommodation to a meal. These data suggest that cisapride may provide benefit to patients with impaired postprandial relaxation of the fundus.

Adult↗
PubMed1998

Actions of the 5-hydroxytryptamine 1 receptor agonist sumatriptan on interdigestive gastrointestinal motility in man.

BACKGROUND: Pharmacological studies of the enteric nervous system have shown the presence of several subtypes of 5-hydroxytryptamine (5HT) receptor, which might be involved in control of the migrating motor complex. AIMS: To study the effect of sumatriptan, an agonist of enteric neuronal 5HT1p receptors, on interdigestive motility in man. SUBJECTS AND METHODS: In 12 healthy subjects, interdigestive motility was recorded manometrically in the upper gastrointestinal tract. In seven subjects blood samples were drawn every 15 minutes for radioimmunoassay of motilin and somatostatin. After two phase 3s of the migrating motor complex, 6 mg of sumatriptan was administered subcutaneously. Recording continued until two more phase 3s had occurred. RESULTS: Sumatriptan induced a premature phase 3 in the jejunum after a median of 10 (8) minutes. The duration of the migrating motor complex cycle was shortened at the expense of phase 2. After sumatriptan, plasma somatostatin concentrations were reduced and gastric phase 3s were suppressed, although median motilin concentrations and the occurrence of plasma motilin peaks were not affected. Phase 3s of the migrating motor complex preceding sumatriptan were associated with motilin peaks, while phase 3s after sumatriptan were not. Furthermore, pretreatment with sumatriptan prevented the induction of a gastric phase 3 by the motilin agonist erythromycin. CONCLUSIONS: Administration of the 5HT1P receptor agonist sumatriptan induces a premature intestinal phase 3, suppresses gastric phase 3s, prevents induction of a gastric phase 3 by erythromycin, and reduces plasma somatostatin concentrations.

Adult↗
PubMed1998

Ambulatory gastrojejunal manometry in severe motility-like dyspepsia: lack of correlation between dysmotility, symptoms, and gastric emptying.

BACKGROUND: Previous studies have failed to identify manometric patterns of gastrointestinal motor activity that can distinguish dyspepsia from health. AIMS: To test the hypothesis that the combined use of prolonged, ambulatory, antrojejunal manometry and computer aided analysis in patients selected for the severity of their symptoms could reveal new insights into gastrointestinal motor activity in patients with severe motility-like dyspesia. METHODS: Twenty four hour antrojejunal ambulatory manometry was performed in 14 patients and 10 healthy volunteers. Parameters characterising digestive and fasted motility were obtained by a validated computer program and visual analysis. Scoring systems quantified the degree of dysmotility as well as the severity of symptoms. Gastric emptying times were measured in each patient. RESULTS: There was a high prevalence of antral and jejunal dysmotility both during the interdigestive period (71% of patients) and in the postprandial period (78%). During the interdigestive period there was a reduced incidence of antral and jejunal phases, a larger contribution of phase 2 during migrating motor complex cycles, and aberrant configuration of jejunal phase 3 in 29% of patients. Postprandially, the most frequent finding was antral (29% of patients) or jejunal (29%) hypomotility or hypermotility. Minute rhythm was present both during the postprandial (29% of patients) and the interdigestive period (21%). There was no positive correlation between symptom scores, gastric half emptying times, or motility scores. CONCLUSION: Even with the use of prolonged recordings and advanced computer aided analysis, it is not possible to identify a specific motor pattern which can discriminate patients with severe motility-like dyspepsia from those with other diseases or even healthy individuals. Clinical symptoms or gastric half emptying times are poor predictors of gastrointestinal dysmotility in patients with functional dyspepsia.

Adolescent↗
PubMed1998

Involvement of two different pathways in the motor effects of erythromycin on the gastric antrum in humans.

BACKGROUND: During the interdigestive state in humans, erythromycin 40 mg induces a premature activity front that starts in the stomach, while erythromycin 200 mg induces a prolonged period of enhanced antral contractile activity. AIMS: To study the involvement of a cholinergic pathway in the motor effects of erythromycin using the muscarinic antagonist atropine and the neural 5-HT1 receptor agonist sumatriptan. METHODS: In 30 healthy volunteers, fasted antroduodenojejunal motor activity was studied by stationary manometry. Placebo (n = 10), atropine (15 micrograms/kg intravenous bolus plus 15 micrograms/kg/h over 30 minutes; n = 10), or sumatriptan (6 mg subcutaneously; n = 10) was administered, followed by infusion of erythromycin 40 mg or 200 mg. RESULTS: After placebo, erythromycin 40 mg induced a premature activity front with gastric onset after 19.1 (1.7) minutes in all volunteers. After atropine, erythromycin 40 mg failed to induce a premature activity front during a 60 minute period in all volunteers (p < 0.001), while sumatriptan prevented the induction of a premature activity front during a 60 minute period in all but one volunteer (p < 0.005). The number of antral contractions and their mean amplitude in the 60 minutes after erythromycin 200 mg did not differ significantly after atropine or sumatriptan versus placebo. CONCLUSIONS: The antral motor effects of erythromycin in humans are mediated via different pathways. The induction of a premature activity front is mediated through activation of an intrinsic cholinergic pathway, while the induction of enhanced antral contractile activity may be mediated via a pathway potentially involving activation of a muscular receptor.

Anti-Bacterial Agents↗
PubMed1998

5-Hydroxytryptamine-1 receptor activation inhibits endocrine pancreatic secretion in humans.

The selective 5-hydroxytryptamine-1 receptor agonist sumatriptan inhibits exocrine pancreatic function in humans. No data are available on the effect of sumatriptan on fasting and postprandial endocrine pancreatic function in humans. To elucidate the influence of 5-hydroxytryptamine-1 receptor activation by sumatriptan on endocrine pancreatic function and blood glucose homeostasis, we determined plasma levels of somatostatin, glucagon, pancreatic polypeptide, insulin, and C-peptide before and after subcutaneous administration of sumatriptan (6 mg) in seven healthy volunteers, and we measured blood glucose and insulin plasma levels during an oral glucose tolerance test after placebo and after subcutaneous administration of sumatriptan (6 mg) in seven healthy volunteers. Sumatriptan significantly decreased the mean plasma levels of somatostatin, glucagon, pancreatic polypeptide, insulin and C-peptide (P < 0.001) and also significantly decreased mean and peak plasma levels of insulin after an oral glucose challenge (P < 0.02 and P = 0.04, respectively) without affecting glucose homeostasis. From our study, we speculate that activation of the 5-hydroxytryptamine-1 receptor inhibits endocrine pancreatic secretion.

Adult↗
PubMed1997

[Obstetrics and gynecology in the last 40 years].

In the Netherlands the last 40 years have seen major changes in obstetrics and gynaecology: Progressive expansion of evidence-based medicine. A measurable, greatly improved quality policy during gynaecologists' training and the subsequent period. Increase of diagnostic possibilities during pregnancy (such as real-time echography, Doppler measurements, amniocentesis and umbilical-cord puncture). Foundation of the Landelijke Verloskunde Registratie (LVR. National Obstetrical Registry) in 1982, in which by now 90% of the specialists and 80% of the midwives are participating. Implementation of the 'Dutch model' of obstetrical care. Decrease of the number of home deliveries and increase of the obstetrical interventions. More attention for sex problems. Better results in the treatment of gynaecological tumours. Great progress in the field of reproduction endocrinology (both pharmaceutical and surgical).

Female↗
PubMed1997

Ambulatory small intestinal manometry. Detailed comparison of duodenal and jejunal motor activity in healthy man.

The aim of this study were to provide a detailed comparison of duodenal and jejunal motor activity in healthy individuals by utilizing prolonged ambulatory manometry in combination with computer-aided analysis. Intraluminal pressure profiles were studied in the duodenum and jejunum of 18 healthy volunteers over 24 hr. The subjects ingested two meals, both of 800 kcal and of equal chemical composition, at two different times of the day. Over the whole interdigestive period, phase III motor activity started more frequently distal than proximal to the ligament of Treitz. However, an increasing time of fasting was linearly related to an increasing number of phase IIIs originating proximal to the ligament of Treitz (r = 0.95). Both meals induced a postprandial motor pattern of similar duration and contractile activity. As compared to the jejunum, individual duodenal contractions during the postprandial period and during phase II had a higher duration and amplitude. Propagated clustered contractions occurred more frequently in the duodenum than in the jejunum, both in the interdigestive and digestive state. Jejunal clusters comprised a higher number of individual contractions of lower amplitude and duration. In healthy man duodenal and jejunal motor activity are different, both in the digestive and interdigestive state. The differences include the number of activity fronts traversing these segments of the gut, the number and organization of propagated clustered contractions, and subtle changes in the amplitude, duration, and coordinated propagation of individual contractions. These changes presumably reflect a regulatory capability of the small intestine to modulate the rate of transit of intraluminal content through different segments of the gut.

Adult↗
PubMed1997

Sumatriptan, a selective 5-HT1 receptor agonist, induces a lag phase for gastric emptying of liquids in humans.

Sumatriptan, a 5-hydroxytryptamine1 (5-HT1) receptor agonist at enteric neuronal 5-HT receptors, causes a relaxation of the gastric fundus and inhibition of antral contractile activity. The present study examined the effect of sumatriptan on gastric emptying of solids and liquids in humans. In eight healthy subjects the gastric emptying rate for liquids and solids was measured using the carbon-labeled glycine and octanoic acid breath test after subcutaneous administration of placebo or sumatriptan. Sumatriptan increased the gastric half-emptying time of liquids (P < 0.0005) and induced a prolonged lag phase for liquids (P < 0.0005) in all subjects. Sumatriptan increased gastric half-emptying time (P < 0.005) and the lag phase of solids (P < 0.05) in all subjects. In two healthy subjects gastric emptying of liquids and solids after subcutaneous administration of sumatriptan was studied by radioscintigraphy. Radioscintigraphy confirmed the delayed emptying and the prolonged lag phases after sumatriptan. In conclusion, sumatriptan delays gastric emptying of solids and liquids in healthy subjects. Moreover, sumatriptan induces a lag phase for liquids. The mechanism by which sumatriptan alters gastric emptying remains to be studied.

Adult↗
PubMed1997

Capillary electrophoresis system for hemoglobin A1c determinations evaluated.

Hb A1c is the analyte of choice for monitoring metabolic control in patients with diabetes mellitus. Here we present a new analytical technique for measuring Hb A1c, capillary electrophoresis. The Hb A1c determination is not influenced by the labile Hb A1c fraction or by carbamylated or acetylated hemoglobin derivatives. Also, hemoglobin variants (Hb F, Hb S, and Hb C) do not interfere. This new application of capillary electrophoresis seems to be a valuable analytical tool for measuring Hb A1c in the clinical laboratory.

Blood Protein Electrophoresis↗
PubMed1997

New insights in the pathophysiology of primary motility disorders of the esophagus.

Primary esophageal motility disorders (i.e. achalasia, diffuse spasm and related conditions) but also gastroesophageal reflux disease are characterised by a more or less pronounced dysfunction of esophageal body peristalsis and gastroesophageal sphincter relaxation. A normal interplay between inhibitory and excitatory peripheral nerves in the smooth muscle part of the esophagus is essential for the generation of esophageal peristalsis. The inhibitory nerve pathway determines the timing of the contraction; its neurotransmitter is NO. The excitatory pathway mainly determines the strength of the contraction; the neurotransmitter is acetylcholine. We have recently developed a technique to visualize the effect of the inhibitory nerves in the human tubular esophagus as a manometric relaxation of an artificial high pressure zone. We used this technique in patients with achalasia, diffuse spasm and related conditions and found an inverse relationship between percent inhibition and progression velocity of the contractions. We have examined with the same technique patients with reflux disease and found in these patients that the occurrence of acid reflux during TLESR's is accompanied by inhibition of the esophagus, whereas in normal controls it is accompanied by excitation. From a pathogenetic viewpoint we conclude as follows. Disorders of the inhibitory nerve pathway result in achalasia, diffuse spasm or related condition. We do not know exactly what happens when the excitatory pathway is diseased; there are arguments that these patients may have reflux disease.

Esophageal Achalasia↗
PubMed1996

Computer-supported analysis of continuous ambulatory manometric recordings in the human small bowel.

An algorithm has been developed for the offline analysis of prolonged manometric recordings in the upper small intestine of humans. Sample data are acquired in the human duodenum and jejunum six solid-state strain-gauge transducers mounted on a silicon catheter that is connected to a portable digital recording device. The data are sampled at 4 Hz and filtered. For accurate calculations, the filtered signals are converted to cubic B-spline functions of order four. Based on an exponential weighted moving average, a base-line is calculated from the signal. Contractions are recognised on the basis of thresholds for minimum amplitude and duration. The developed algorithm calculates properties of these contractions, such as amplitude, duration, area and a motility index. In addition, the program automatically recognises normal motor patterns of the fasted human small intestine, such as the migrating motor complex, and aids in the identification of the postprandial motor pattern. Motor patterns are defined in terms of properties such as contraction frequency and propagation. In a validation procedure using conventional manual analysis, the program correctly identifies the number of individual contractions with a 98% confidence interval and also correctly recognises 96% of phase 3 motor activity.

Algorithms↗
PubMed1996

Transient lower esophageal sphincter relaxations and esophageal body muscular contractile response in normal humans.

BACKGROUND & AIMS: Gastroesophageal reflux frequently occurs during spontaneous transient lower esophageal sphincter relaxations (TLESRs). The aim of this study was to determine the motor activity in the body of the esophagus during TLESRs in 10 healthy subjects. METHODS: Esophageal contractions were recorded 13,8,and 3 cm above a sleeve that measured LES pressure. A balloon was inflated 8 cm above the sleeve to induce an esophageal tonic contraction (artificial high-pressure zone). RESULTS: No relaxation of the artificial high-pressure zone was detected at the onset or during spontaneous TLESRs before gastroesophageal reflux. Esophageal acidification provoked no changes or increased the pressure in the artificial high-pressure zone by 47.9% +/- 12% When gastroesophageal reflux abruptly distended the esophagus (common cavity), a relaxation of the artificial high-pressure zone of 51.1% +/- 6.6% was observed in 78% of the instances. Deglutitive or secondary contractions during spontaneous TLESRs traveled down the esophagus in 96.5% of the instances. CONCLUSIONS: Stimuli that induced spontaneous TLESRs did not by themselves inhibit muscle contractility in the body of the esophagus. Acidification without distention of the lower esophagus frequently increased esophageal tonic contractility. Abrupt lower esophageal distention by reflux of air or acid partially relaxed the artificial high-pressure zone in the esophageal body, probably to assist gastric venting.

Adolescent↗
PubMed1996

Secondary peristaltic contractions, like primary peristalsis, are preceded by inhibition in the human esophageal body.

Swallow-induced esophageal peristalsis is preceded by a wave of inhibition in the esophageal body. The aim of this study was to determine whether a similar wave of inhibition precedes secondary peristalsis. Primary and secondary peristalsis were studied in 6 healthy subjects. Inhibition was visualized as relaxation of an artificial high-pressure zone which was created in the esophageal body by the inflation of a small intraesophageal balloon. Secondary peristaltic contractions induced by injection of 10 ml of air in the proximal esophagus or secondary peristaltic contractions spontaneously occurring after repeated swallowing were preceded by inhibition similar to that observed in primary peristalsis (96.4 +/- 2.8%, 93.2 +/- 4.2% and 91.5 +/- 3.3%) respectively. It is concluded that physiologically triggered secondary peristaltic contractions are preceded by inhibition in the esophageal body.

Adult↗